1. Field of the Invention
The present invention relates to an occupant restraint system such as an airbag device, to secure safety for an occupant in the event of a vehicle collision. More particularly, the present invention relates to an occupant restraint system wherein the operational mode is variable according to the size of a person sitting on a seat.
2. Description of the Related Art
Vehicles are equipped with occupant restraint systems such as airbag devices for protecting occupants in the event of vehicle collision and, in the United States, it has been considered to require vehicles to be provided with such restraint systems by regulation. As an example, an airbag device includes an inflator and an airbag wherein the inflator actuates to inflate the airbag and the inflated airbag restrains an occupant, thereby preventing the occupant from colliding with a vehicle body or preventing the occupant from being thrown out of the vehicle. The occupant restraint system is directed to secure the safety for an occupant by restraining the body of the occupant in the event of a vehicle collision.
In case where the occupant is an infant or a child, however, the airbag may injure the infant or the child if the airbag is deployed in a normal mode. Therefore, it is required to detect the constitution of the occupant, and to deploy the airbag in a mode different (including a case of not deploying the airbag) from the normal mode when it is detected that the occupant is an infant or a child. However, means for achieving the aforementioned operation have never been realized.